Compressional behavior of solid NeHe2 up to 90 GPa.

NeHe(2) was compressed to about 90 GPa using a diamond anvil cell technique. The crystal structure was confirmed to be stable with hexagonal symmetry in the investigated pressure range and its p-V equation of state was determined by angular dispersive x-ray diffraction with synchrotron radiation. With the help of ab initio calculations, the compressibility and inter-atomic distances of NeHe(2) were compared with those of a helium and neon mixture of the same composition. This study shows that the bulk modulus of NeHe(2) is between those of neon and helium and that linear compressibilities of the inter-atomic distances are different from those of the elementary solids. This material can be a pressure-transmitting medium, providing both a large sample space and good quasi-hydrostatic conditions.